Oxidative desulfurization of dibenzothiophene catalyzed by α-MnO2 nanosheets on palygorskite using hydrogen peroxide as oxidant

High-Throughput Screening Strategy for Electrocatalysts for Selective Catalytic Oxidation of Formaldehyde to Formic Acid

Electrocatalytic oxidation of formaldehyde (FOR) is an effective way to prevent the damage caused by formaldehyde and produce high-value products. A screening strategy of a single-layer MnO2-supported transition metal catalyst for the selective oxidation of formaldehyde to formic acid was designed by high-throughput density functional calculation. N-MnO2@Cu and MnO2@Cu are predicted to be potential FOR electrocatalysts with potential-limiting steps (PDS) of 0.008 and -0.009 eV, respectively. Electronic structure analysis of single-atom catalysts (SACs) shows that single-layer MnO2 can regulate the spin density of loaded transition metal and thus regulate the adsorption of HCHO (Ead), and Ead is volcanically distributed with the magnetic moment descriptor -|mM - mH|. In addition, the formula quantifies Ead and |mM - mH| to construct a volcano-type descriptor α describing the PDS [ΔG(*CHO)]. Other electronic and structural properties of SACs and α are used as input features for the GBR method to construct machine learning models predicting the PDS (R2 = 0.97). This study hopes to provide some insights into FOR electrocatalysts.

Deep Oxidative Desulfurization of Planar Compounds Over Functionalized Metal-Organic Framework UiO-66(Zr): An Optimization Study

This study aims to determine the catalytic activity and stability of ligand-modified UiO-66 with different functional groups (-NO2, -OH) in deep oxidative desulfurization from a model fuel (MF). The planar sulfur compounds included dibenzothiophene (DBT), 2-methylbenzothiazole (2-MB), and 4,6-dimethyldibenzothiophene (4,6-DMDBT) in n-dodecane as the fuel phase. The synthesized functionalized metal-organic framework (MOF) samples were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), nitrogen adsorption-desorption analysis, and microwave plasma-atomic emission spectrometer (MP-AES). The experiment assessment and desulfurization reaction optimization were carried out by the central composite design methodology. Response surface methodology and analysis of variance were employed to evaluate the individual process factors, their interactions, and sulfur removal responses. The responses showed that the oxidation of the planar compounds declined following the sequence DBT > 2-MB ≫ 4,6-DMDBT for all the MOFs. The findings revealed that at 66.7 °C, 3.0 equiv of oxidative agent over sulfur and 9.7 of MOF over sulfur by weight achieved the highest removal efficiency of 98.68% DBT, 93.23% 2-MB, and 69.32% 4,6-DMDBT for UiO-66-NO2 as a catalyst from the model fuel. It was also observed that UiO-66-NO2 had a higher efficiency in deep oxidative desulfurization when compared to other UiO-66-based catalysts used in the current study. Under optimal conditions, all the MOFs showed acceptable catalytic activity and reusability after four runs, although gradual loss of activity was observed.

Process Optimization for Catalytic Oxidation of Dibenzothiophene over UiO-66-NH2 by Using a Response Surface Methodology

This research investigates the catalytic performance of a metal-organic framework (MOF) with a functionalized ligand-UiO-66-NH₂-in the oxidative desulfurization of dibenzothiophene (DBT) in n-dodecane as a model fuel mixture (MFM). The solvothermally prepared catalyst was characterized by XRD, FTIR, ¹H NMR, SEM, TGA, and MP-AES analyses. A response surface methodology was employed for the experiment design and variable optimization using central composite design (CCD). The effects of reaction conditions on DBT removal efficiency, including temperature (X ₁), oxidant agent over sulfur (O/S) mass ratio (X ₂), and catalyst over sulfur (C/S) mass ratio (X ₃), were assessed. Optimal process conditions for sulfur removal were obtained when the temperature, O/S mass ratio, and C/S mass ratio were 72.6 °C, 1.62 mg/mg, and 12.1 mg/mg, respectively. Under these conditions, 89.7% of DBT was removed from the reaction mixture with a composite desirability score of 0.938. From the results, the temperature has the most significant effect on the oxidative desulfurization reaction. The model F values gave evidence that the quadratic model was well-fitted. The reusability of the MOF catalyst in the ODS reaction was tested and demonstrated a gradual loss of activity over four runs.

A Novel Synthetic Nano-Catalyst (Ag2O3/Zeolite) for High Quality of Light Naphtha by Batch Oxidative Desulfurization Reactor

Oxidative desulfurization process (ODS), enhanced with a novel metal oxide (Ag ions) as an active component over nano-zeolite that has not been reported in the literature, is used here to improve the fuel quality by removing mercaptan (as a model sulfur compound in the light naphtha). Nano-crystalline (nano-support (Nano-zeolite)) composite is prepared by Incipient Wetness Impregnation method loaded with a metal salt to obtain 0.5, 1 and 1.5% of Ag2O3 over Nano-zeolite. The new homemade nano-catalysts (Ag2O3/Nano-zeolite) prepared are characterized by Brunauer–Emmett–Teller (BET) (surface area, pore volume and pore size), X-ray Diffraction (XRD), Fourier Transform Infra Red (FTIR), and Scanning Electron Microscopy (SEM) analysis. The ODS process is then used to evaluate the performance of the catalysts for the removal of sulfur at different reaction temperatures (80–140 °C) and reaction times (30–50 min) in a batch reactor using the air as oxidant. 87.4% of sulfur removal has been achieved using 1% silver oxide loaded on Nano zeolite (1% of Ag2O3/Nano-zeolite) giving a clear indication that our newly designed catalyst is highly efficient catalyst  in the removal of sulfur compound (mercaptan) from naphtha. A new mechanism of chemical reaction for sulfur removal by oxygen using the new homemade catalyst (Ag2O3/Nano-zeolite) prepared has been suggested in this study. The best kinetic model parameters of the relevant reactions are also estimated in this study using pseudo first order technique based on the experimental results. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Synthesis of novel magnetic ionic liquids as high efficiency catalysts for extraction-catalytic oxidative desulfurization in fuel oil

Deep desulfurization of magnetic ionic liquids [C₄(mim)₂]Cl₂/2FeCl₃.